Vehicle seat

Abstract

Provided is a vehicle seat which has a simple structure, prevents the lower back region of an occupant from sinking into the seat back, induces backward rotation of the entire upper body when a rear-end collision occurs, and reduces the degree to which the neck region of the occupant independently tilts backward, and is therefore able to effectively reduce the load on the neck region and so on of the occupant. A vehicle seat is provided with a neck-burden reduction element that, during a rear-end collision, causes a greater amount of backward movement of a connection point between the neck region and a torso region of the occupant than the amount of backward movement of a lower torso region of the occupant, and causes an upper torso region of the occupant to sink into the seat back.

What is claimed is: 
     
       1. A vehicle seat comprising:
 a seat back frame comprising:
 side portions located on both sides of the seat back frame; 
 an upper frame disposed in an upper area of the seat back frame; and 
 a lower frame disposed in a lower area of the seat back frame and extending between the side portions; 
 
 a lower member disposed between the side portions and mounted on the lower frame; and 
 a reclining shaft for a reclining mechanism; 
 wherein:
 the lower member covers a front side of the reclining shaft in a seat front-to-rear direction; 
 each end portion of the lower member in a seat right-to-left direction is separated from the side portions of the seat back frame; and 
 a front surface of the lower member has a first front portion and a second front portion that is separated from the first front portion by a relief area. 
 
 
     
     
       2. The vehicle seat according to  claim 1 , wherein:
 each of the side portions comprises an inward extension portion at a front end of the side portion in the seat front-to-rear direction that extends toward an inner side of the seat; and 
 the end portion of the lower member in the seat right-to-left direction is located on the inner side of the seat relative to an inner end of the inward extension portion. 
 
     
     
       3. The vehicle seat according to  claim 1 , wherein:
 a pillar support portion is provided on the upper frame; and 
 an inclination angle of the pillar support portion relative to a vertical direction and an inclination angle of the front surface of the lower member relative to the vertical direction are different. 
 
     
     
       4. The vehicle seat according to  claim 1 , wherein:
 the relief area is a split in the front surface of the lower member. 
 
     
     
       5. The vehicle seat according to  claim 1 , wherein:
 the relief area is an empty space in the front surface of the lower member. 
 
     
     
       6. The vehicle seat according to  claim 1 , wherein:
 the relief area is a recess in the front surface of the lower member. 
 
     
     
       7. A vehicle seat comprising:
 a seat back frame comprising:
 side portions located on both sides of the seat back frame; 
 an upper frame disposed in an upper area of the seat back frame; and 
 a lower frame disposed in a lower area of the seat back frame and extending between the side portions; and 
 
 a lower member disposed between the side portions and mounted on the lower frame; 
 wherein:
 each end portion of the lower member in a seat right-to-left direction is separated from the side portions of the seat back frame by a first space between the end portion of the lower member and the side portion; 
 the lower frame comprises a flange that is bent toward a seat front direction and extends along an upper edge of the lower frame; 
 an end portion of the flange in the seat right-to-left direction is separated from the side portions of the seat back frame by a second space between the end portion of the flange and the side portion; 
 a width of the second space in the seat right-to-left direction is smaller than a width of the first space in the seat right-to-left direction and a projection of the width of the second space onto the first space is within the width of the first space; 
 the lower member comprises a front surface and an upper surface that extends rearward from an upper end of the front surface; and 
 a rear end of the upper surface overlaps with the flange and is bent downward. 
 
 
     
     
       8. The vehicle seat according to  claim 7 , wherein:
 the lower frame comprises an inclined portion at an upper edge portion thereof that is inclined relative to a horizontal direction; and 
 the inclined portion is located outside of the end portion of the lower member in the seat right-to-left direction. 
 
     
     
       9. The vehicle seat according to  claim 7 , wherein:
 a third space is provided at a central portion of a front surface of the lower member in the seat right-to-left direction. 
 
     
     
       10. The vehicle seat according to  claim 7 , wherein:
 the lower member comprises a front surface and an upper surface that extends rearward from an upper end of the front surface; and 
 the front surface is connected to the lower frame. 
 
     
     
       11. The vehicle seat according to  claim 7 , wherein:
 the flange is located outside of the end portion of the lower member in the seat right-to-left direction.